Chemical composition of leaf and flower essential oils from <i>Cyanthillium cinereum</i> (L.) H. Rob., characterization of a new bergamotenal

The leaf and flower essential oils from Cyanthillium cinereum (Asteraceae), growing wild in Côte d’Ivoire were investigated, using a combination of chromatographic [CC, GC(RI)] and spectroscopic [MS, 13C-NMR] techniques. A novel sesquiterpene identified as (E)-trans-β-bergamotenal, was characterized. The oils from both plant parts were found to be rich in sesquiterpene hydrocarbons with concentration ranging from 78.4–87.6% in the flowers, and 72.1–91.8% in the leaves. In total, 43 constituents (91.5–96.7%) and 37 constituents (92.2–96.4%) were identified in the flower, and leaf oils, respectively. Major components of the flower oil were γ-humulene (17.4–37.4%) and (E)-β-caryophyllene (19.7–34.1%), followed by trans-β-bergamotene (3.4–13.1%). The leaf oil composition was dominated by (E)-β-caryophyllene (40.1–56.8%), with notable amounts of caryophyllene oxide (1.4–17.5%), germacrene D (1.8–11.4%), α-humulene (7.1–9.0%), guaia-6,10(14)-diene (3.6–8.9%) and γ-humulene (0.3–5.9%). The hierarchical clustering analysis showed that flower and leaf essential oils from Côte d’Ivoire are grouped in two distinct clusters and differed from samples collected in other countries.